Oxytocin is today widely spoken of as a "feel good" hormone. Recent research has increased interest in the hormone and its role in social and sexual interactions, as well as its importance for complex behavioral patterns. There is evidence that oxytocin is released during physical contact and is said to suppress anxiety and stress. In animals and humans, oxytocin, which is a neuropeptide and likewise a hormone, is necessary for parturition and lactation. Synthesis of oxytocin occurs in brain neurons and in specific organs involved in reproduction.

Genetic parameters for four leg conformation traits in dogs (Canis lupus familiaris) are in this literature review summarized to investigate whether selective breeding could be useful to improve purebred dogs´ health and welfare. The four traits are leg length, leg weakness, hip joint and elbow joint conformation. When summarized, the genetic parameters are compared with genetic parameters affecting in pigs (Sus scrofa). Of the four traits, hip and elbow conformations were mostly studied in dogs. However, these traits were not widely studied in pigs.

The purpose of this study was to compile when and why piglets die during the suckling peri-od. Piglet mortality is an important factor influencing the profitability of piglet production. There are many factors that play a role and interact whit each other. This study summarizes when the piglets die during the suckling period and reasons why the piglets die. The infor-mation given is crushed, illness, management/environmental, genetic influence and piglet birth weight/farrowingprocess.

Claw health has been recorded by claw trimmers at trimming in Sweden since 1996, but data was then captured at each AI association. From 2003 data was captured by central scanning and entered directly to the national cow data base at the Swedish Dairy Association (SDA). This reporting was introduced because SDA wanted to be able to use these records to improve dairy cow claw health by breeding. It is desirable with cows that have healthy claws, because poor claw health can contribute to impaired production and fertility. The claw health report begins with some information about herd, claw trimmer, date et cetera and continues with the part where the claw health is recorded. Here the ID of each cow is filled in and on the same row the conditions for dermatitis, heel horn erosion, sole haemorrhage and sole ulcer are recorded as no lesion (blank), slight lesion (/) or severe lesion (X).

Over time, species colonize new areas naturally or through humans. The colonizers areoften few and founded populations represent only a fraction of the genetic diversityexisting in the original population. If the established population becomes isolated afterthe colonization event genetic diversity will remain low and if the population, in addition,remains small in size for an extended period this will lead to increased inbreeding andpossibly inbreeding depression. Metrioptera roeselii is a common species with awidespread distribution in continental Europe. During the last century, it has expanded tothe Scandinavian Peninsula which is separated from continental Europe by the Baltic Sea.My aim was to test the hypothesis that individuals in isolated populations in Scandinaviaincluding Denmark and the Baltic Sea islands are smaller than individuals in thecontinuous part of its distribution due to low genetic diversity and lacking incoming geneflow.

AbstractThe purpose of this bachelor thesis is to describe the use of artificial insemination (AI) in sheep and discuss the possibilities for AI in Sweden. Male and female fertility, heat detection, semen handling and insemination techniques in sheep are described. Advantages and disadvantages of AI are discussed. In order to achieve genetic progress it is important with well planned and implemented breeding programs. The Swedish Sheep Recording Scheme and computer software from Elitlamm are the basis for sheep breeding in Sweden.

The purpose of this literature study was to describe the seasonal reproduction in sheep and the presence of genetic variation in fertility traits. Methods to induce oestrus are described and the possibilities to change the reproduction season through breeding are discussed. Sheep have a pronounced seasonality in their reproduction. Mating season starts in the fall and the lambs are born during the spring because this is the most beneficial time. The market request for lamb meat has increased and therefore it is desirable with ewes that could get pregnant all year round.

In today?s genetic evaluation of Swedish beef cattle, mainly traits that are directly related to productivity are measured. However, other traits, such as temperament and mature cow weight affect the economy of the farmer, as well as the welfare of the animals. This thesis evaluates possible ways of measuring new traits, with focus on temperament and mature weight of suckler cows. The goal is to examine the possible benefits of including these traits in the Swedish breeding scheme.

Dilated cardiomyopathy (DCM) is the second most common heart disease in dogs. Since the disease is seen more frequently in certain breeds, among them Newfoundland dogs, a genetic factor is suspected. This study was partly undertaken to investigate whether there is a significant sex predilection regarding DCM. Moreover, the difference in mean age of death between male dogs and females with DCM was investigated, as well as males and females dying from DCM compared to dying from other reasons (i.e. without DCM).

As the quality of internationally competing horses is increasing, a debate concerning the breeding goal of the Swedish Warmblood horse has arisen. Some people claim that the breeding goal should be divided into two separate goals in the future; one for show jumping horses and another one for dressage horses. At the same time others claim that since the largest group of people using the Swedish Warmblood horse today is amateur riders, the needs of these riders should be taken into a larger consideration in the breeding program. The largest emphasis in this matter is on the horses? temperament. The objective of the study was to investigate what the majority of the Swedish horse people think about a variety of questions concerning today?s breeding goal of the Swedish Warmblood horse.

Tail-biting in pigs is an animal welfare issue and in Sweden during 2002 the producers lost tree million Swedish crowns because of tail biting. This economic loss depends on the pigs which are discarded at slaughter because of tail biting. Tail biting can be separated into two stages, "pre-injury" and "injury". The aim of this study is to investigate if tail biting depends on environment or genetic background.A lot of research on the environments effects on the behaviour of pigs but not so much on the genetic effects has been performed. The frequency of tail biting in pig farms influence among others of environment enrichment, ventilation, gender and breed of the pig.

Almost for as long as there has been breeding on bovine species, there has been a wish to have a higher proportion of offspring of either one or the other gender. In dairy cattle, heifers are more valuable, while in beef stock bulls are preferred. Semen is sorted based on the difference in DNA content between the X- and Y-chromosome in the genome of the sperm. X-chromosomes contain on average between 3,70 to 4,22% more genetic material than the Y-chromosome. Commercially it is the method of flow cytometry that is being used, which is always under improvement.

Tail-biting in pigs is an animal welfare issue and in Sweden during 2002 the producers lost tree million Swedish crowns because of tail biting. This economic loss depends on the pigs which are discarded at slaughter because of tail biting. Tail biting can be separated into two stages, "pre-injury" and "injury". The aim of this study is to investigate if tail biting depends on environment or genetic background.A lot of research on the environments effects on the behaviour of pigs but not so much on the genetic effects has been performed. The frequency of tail biting in pig farms influence among others of environment enrichment, ventilation, gender and breed of the pig.

Claw diseases are common diseases in modern dairy production. They are painful for the cow and costly for the producer. Differences in the prevalence of claw disease depending on housing system have previously been observed. This raises the question if there are genotype by environment (GxE) interactions for claw diseases in different housing systems. To investigate this claw trimming records for Swedish Red dairy cattle (SR) and Swedish Holstein cows (SH) were retrieved from the Swedish Dairy Association.

Tail-biting in pigs is an animal welfare issue and in Sweden during 2002 the producers lost tree million Swedish crowns because of tail biting. This economic loss depends on the pigs which are discarded at slaughter because of tail biting. Tail biting can be separated into two stages, "pre-injury" and "injury". The aim of this study is to investigate if tail biting depends on environment or genetic background.A lot of research on the environments effects on the behaviour of pigs but not so much on the genetic effects has been performed. The frequency of tail biting in pig farms influence among others of environment enrichment, ventilation, gender and breed of the pig.